Make sure the motorcycle has a manual transmission
Turn the ignition on
Put the bike in second gear
Pull in the clutch
Have the bike moving by pushing it or rolling downhill
Reach a moderate speed
Release the clutch quickly while giving a little throttle
If the engine starts, pull the clutch back in immediately
Keep the engine running with gentle throttle
If it does not start, repeat the process
Stop and check for fuel, battery, or ignition issues if it still will not start